Copyright (c) 2003, 2014 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM - Initial API and implementation
/*******************************************************************************
 * Copyright (c) 2003, 2014 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM - Initial API and implementation
 *******************************************************************************/
package org.eclipse.core.internal.jobs;

import org.eclipse.core.internal.runtime.RuntimeLog;
import org.eclipse.core.runtime.*;
import org.eclipse.core.runtime.jobs.*;
import org.eclipse.osgi.util.NLS;

Responsible for notifying all job listeners about job lifecycle events.  Uses a
specialized iterator to ensure the complex iteration logic is contained in one place.
/**
 * Responsible for notifying all job listeners about job lifecycle events.  Uses a
 * specialized iterator to ensure the complex iteration logic is contained in one place.
 */
class JobListeners {
	interface IListenerDoit {
		void notify(IJobChangeListener listener, IJobChangeEvent event);
	}

	private final IListenerDoit aboutToRun = IJobChangeListener::aboutToRun;
	private final IListenerDoit awake = IJobChangeListener::awake;
	private final IListenerDoit done = IJobChangeListener::done;
	private final IListenerDoit running = IJobChangeListener::running;
	private final IListenerDoit scheduled = IJobChangeListener::scheduled;
	private final IListenerDoit sleeping = IJobChangeListener::sleeping;

	
The global job listeners.
/**
	 * The global job listeners.
	 */
	protected final ListenerList<IJobChangeListener> global = new ListenerList<>(ListenerList.IDENTITY);

	
TODO Could use an instance pool to re-use old event objects
/**
	 * TODO Could use an instance pool to re-use old event objects
	 */
	static JobChangeEvent newEvent(Job job) {
		JobChangeEvent instance = new JobChangeEvent();
		instance.job = job;
		return instance;
	}

	static JobChangeEvent newEvent(Job job, IStatus result) {
		JobChangeEvent instance = new JobChangeEvent();
		instance.job = job;
		instance.result = result;
		return instance;
	}

	static JobChangeEvent newEvent(Job job, long delay) {
		JobChangeEvent instance = new JobChangeEvent();
		instance.job = job;
		instance.delay = delay;
		return instance;
	}

	
Process the given doit for all global listeners and all local listeners
on the given job.
/**
	 * Process the given doit for all global listeners and all local listeners
	 * on the given job.
	 */
	private void doNotify(final IListenerDoit doit, final IJobChangeEvent event) {
		//notify all global listeners
		for (IJobChangeListener listener : global) {
			try {
				doit.notify(listener, event);
			} catch (Throwable e) {
				handleException(listener, e);
			}
		}
		for (IJobChangeListener listener : ((InternalJob) event.getJob()).getListeners()) {
			try {
				doit.notify(listener, event);
			} catch (Throwable e) {
				handleException(listener, e);
			}
		}
	}

	private void handleException(IJobChangeListener listener, Throwable e) {
		//this code is roughly copied from InternalPlatform.run(ISafeRunnable),
		//but in-lined here for performance reasons
		if (e instanceof OperationCanceledException)
			return;
		String pluginId = JobOSGiUtils.getDefault().getBundleId(listener);
		if (pluginId == null)
			pluginId = JobManager.PI_JOBS;
		String message = NLS.bind(JobMessages.meta_pluginProblems, pluginId);
		RuntimeLog.log(new Status(IStatus.ERROR, pluginId, JobManager.PLUGIN_ERROR, message, e));
	}

	public void add(IJobChangeListener listener) {
		global.add(listener);
	}

	public void remove(IJobChangeListener listener) {
		global.remove(listener);
	}

	public void aboutToRun(Job job) {
		doNotify(aboutToRun, newEvent(job));
	}

	public void awake(Job job) {
		doNotify(awake, newEvent(job));
	}

	public void done(Job job, IStatus result, boolean reschedule) {
		JobChangeEvent event = newEvent(job, result);
		event.reschedule = reschedule;
		doNotify(done, event);
	}

	public void running(Job job) {
		doNotify(running, newEvent(job));
	}

	public void scheduled(Job job, long delay, boolean reschedule) {
		JobChangeEvent event = newEvent(job, delay);
		event.reschedule = reschedule;
		doNotify(scheduled, event);
	}

	public void sleeping(Job job) {
		doNotify(sleeping, newEvent(job));
	}
}